This application claims the priority of German Patent Document No. DE 101 31 433.7, filed Jun. 29, 2001, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a shifting system and method for a motor vehicle transmission.
German Patent Document DE 39 24 318 A1 discloses a shifting system for a motor vehicle transmission which comprises a steering column shift lever which can be moved in two directions arranged orthogonal with respect to one another. The steering column shift lever is changeable along the first direction into at least one forward-drive position (D) as well as an idling position (N) and, along the second direction, into positions for the successive (sequential) gear selection xe2x80x9c+xe2x80x9d, xe2x80x9cxe2x88x92xe2x80x9d.
It is an object of the invention to provide a shifting system which is as cost-effective as possible.
The object is advantageously achieved according to the preferred embodiments of the present invention as described hereinafter.
According to an advantage of the invention, no blocking mechanism is required to prevent a shift from D to R by way of N at relatively high speeds, such as speeds above 3 km/h, in order to prevent damage to the transmission and to implement for the driver a uniformity between the steering column shift lever position and the shifting position engaged in the motor vehicle transmission. The implementation of a mechanical blocking for preventing a movement from D to R would be particularly critical with respect to time. In this context, critical with respect to time means that it would have to be checked extremely rapidly whether a threshold speed valuexe2x80x94for example, 3 km/hxe2x80x94is exceeded. When this is determined, the movement from N to R would have to be blocked in a flash. As a result of the invention, such a costly blocking will advantageously be avoided.
According to another advantage of the invention, the driver""s selection can be detected as a driving range desire. Shifting systems, called xe2x80x9cshift-by-wire systemsxe2x80x9d, have the advantage that, in a simple and cost-effective manner, plausibility controls can be carried out between the motor vehicle transmission and the driver""s. Thus, safety-oriented and comfort-oriented parameters can easily intervene in transmission control. In addition, xe2x80x9cshift-by-wire systemsxe2x80x9d, the transmission can be freely positioned in relation to the steering column shift lever, and has cost advantages with respect to the development expenditures for model reworking.
Another advantage of the shifting system according to the invention is that it complies with the requirements of various important countries and can therefore be sold without modifications in those countries and therefore in large quantities.
Another advantage is the fact that space becomes available because the shift lever does not have to be disposed on the center console. This space can particularly advantageously be used for a holder for beverage cans/bottles which, especially in the U.S., is an advantage particularly appreciated by the customer. This arrangement also results in cost advantages because of the increased sales.
In accordance with a preferred embodiment of the invention, a haptic feedback is implemented for the vehicle driver.
In accordance with another preferred embodiment of the invention, a change from known systems by the vehicle driver is facilitated because the steering column shift lever has the customary positions P-R-N-D.
In accordance with a particularly cost-effective embodiment of the invention, the not time-critical blocking of the steering column shift lever against a movement into the parking position is prevented by means of a block. This movement is not critical with respect to time because the parking position is normally an end position of the steering column shift lever. Since no position behind the parking position must be operated by the steering column shift lever, in the normal driving operation, the above-mentioned blocking device may always be disengaged. Accordingly, a movement of the steering column shift lever into the parking position is prevented.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.